The subject matter herein relates generally to electrical switching devices that are configured to control the flow of an electrical current therethrough.
Electrical switching devices (e.g., contactors, relays) exist today for connecting or disconnecting a power supply to an electrical device or system. For example, an electrical switching device may be used in an electrical meter that monitors power usage by a home or building. Conventional electrical devices include a housing that receives a plurality of input and output terminals and a mechanism for electrically connecting the input and output terminals. Typically, one of the terminals includes a spring arm that is movable between an open position and a closed position to electrically connect the input and output terminals. In some switching devices, a solenoid actuator is operatively coupled to the spring arm to move the spring arm between the open and closed positions. When the solenoid actuator is triggered or activated, the solenoid actuator generates a predetermined magnetic field that is configured to move the spring arm to establish an electrical connection. The solenoid actuator may also be activated to generate an opposite magnetic field to move the spring arm to disconnect the input and output terminals.
However, a switching device that uses a solenoid actuator as described above is not without disadvantages. For example, to control overtravel and/or to ensure adequate contact pressure between the input and output terminals, the switching devices typically include an overtravel spring. Some systems use a separate spring that is assembled to the spring arm to control the amount of overtravel and/or contact pressure force on the spring arm. Having separate components and interconnected parts within the housing may lead to greater costs and time spent to assemble the switching devices. Other systems design the spring arm to perform the function of controlling overtravel and/or contact pressure. Spring arms designed to have the dual function of controlling overtravel and/or contact pressure as well as carrying current between the input and output terminals results in trade-offs in one or both functions, as well as increases the overall cost of the spring arm by over-designing the spring arm to satisfy one or both functions. It is difficult to balance the spring arm design to satisfy both electrical properties of the switch and spring force properties of the contact overtravel. For example, having a thicker spring arm material may be better for electrical performance but may reduce the spring flexibility of the spring arm, and vice versa.
Accordingly, there is a need for electrical switching devices that simplify and reduce the cost of overtravel spring design. There is a need for separating the electrical and spring properties of the spring arm and allow for contact force optimization for the system. There is a need for electrical switching devices that may reduce the number of components and simplify the assembling as compared to known switching devices.